Baby Developing inside you

Fetal Development

Baby developing inside you
over the weeks and months
15 week fetus inside


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Week Fifteen: Bones and muscles grow

You are 15 weeks pregnant. (fetal age 13 weeks)
  • Baby is now over 4 inches (10cm) long
  • and weighs about 2.5 ounces (75 grams).
  • He or she can move its arms and make a fist.
  • Fingernails and toenails are present.
  • Baby's skin is still very thin.
15 weeksYour baby's legs have grown longer than the arms and the body is now longer than the head. The bone and marrow that make up your baby's skeletal system are continuing to develop this week. The bones and muscles are continuing to grow. You may begin to feel some fluttering movements as baby kicks, twists and turns; but don't panic if you don't feel movement yet.

Their ears are nearly in position, and the three tiny bones in his middle ear have begun to harden. By the end of the week, the roof of your baby's mouth will be completely formed. The fetus has an adult's taste buds and may be able to savor the mother's meals. The baby's thin skin is covered with ultra fine, downy hair that usually disappears before birth.

The fetal crown to rump length by this week of pregnancy is 4 to 4.5 inches (100 to 115mm). The fetus weighs about 2.5 ounces (75g). It's close to the size of a softball.

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Week By Week Pregnancy Calendar

First Trimester
Week 1   Week 2   Week 3   Week 4   Week 5   Week 6   Week 7  
Week 8   Week 9   Week 10   Week 11   Week 12   Week 13
Second Trimester
Week 14   Week 15   Week 16   Week 17   Week 18   Week 19   Week 20  
Week 21   Week 22   Week 23   Week 24   Week 25   Week 26
Third Trimester
Week 27   Week 28   Week 29   Week 30   Week 31   Week 32   Week 33  
Week 34   Week 35   Week 36   Week 37   Week 38   Week 39   Week 40